D130F Alway room for Improvement

[GeneT]

I've got a couple of D130F's, 4 ohms, set in homebuilt enclosures that I've been using for about 25? Years. I've taken an upswing in my audio interest lately and have been changing things around. A while back I tried to go small with some Bose acousti-(fill in own adj.). They're OK for AV duty but not to be confused with music speakers. We'll after reading a post that "D130 wants 4.6 cuft tuned to 44 Hz for "Extended Bass" alignment" I'm probably in for a good shellacking but I've got mine in 9.9 CuFt Base Reflex enclosures with 13" X 5" port, interior lined with fiberglass. As is they sound pretty good, nice base response. A short story to that effect is a friends father was, at the time, a VP for Sunn Music (guitar amps), after he heard the D130's he looked at me and said "they're not supposed to go that low". Still there is always room for improvement and a smaller cabinet would be a better fit with the room so I'm curious to read the opinions. I also have a couple of 123A-3's (8 ohm) that I was thinking of building up and tossing in with a sub but I like the D130's so much I haven't been very motivated to go there. Harvey Gerst if you're reading this my wife wants to know if you're romantically involved - She loves you (for making/designing the 130's) - Regards, GeneT

[BMWCCA]

Not a silly question since the rationale for the smaller cabinet size came from a spread sheet. Makes you wonder why JBL ever marketed the C35/C37 cabinets with the D130 if the extra size over the C38 Baron actually made the D130 perform worse. I have to believe JBL did at least some subjective listening tests back in the 50's that justified the larger cabinet. I know I've done mine and preferred the larger cabinet. Guess I'll have to dig out my old JBL speaker construction kit and check out what it tells me.

[Harvey Gerst]

I believe we (JBL) always recommended 4 to 6 cubic feet as the best bass reflex volume for our 15" speakers.

Gene, tell your wife that I'm married, but NOT "romantically involved". However, the commute to Washington would be difficult; would she be willing to relocate?

[GeneT]

BMWCCA / Harvey It is a pleasure and honor to rub up posts with folks so astute in the JBL Legacy. Thanks for the comments and if any one has definite information on reccomended volume and port size let me know, as I'd love to make them sound better than they do now. I'm not even opposed to trying a sealed box design. The JBLs are being driven by a HK 730 (30+ year old twin powered) receiver which has plenty of push so a small loss of efficeincy would be acceptable to achieve a better sound. I recently tried replacing the HK with a Onkyo TX-SR800 AV Receiver and while it works well as an AV unit it just wasn't the same for music.

Harvey, I guess I'll have to make sure the wife doesn't start dipping into the frequent flyer miles. - Gene

[Harvey Gerst]

I found this old chart that seems to be fairly accurate:

[GeneT]

Thanks Harvey! If I'm reading the chart correctly I'm tuned for about 41hz now with a volume just over 17,000. The port volume is reasonably close though the port aspect is a little off at 13*5. I was somewhat surprised at how much volume gets dropped for just a 4 or 5 Hz. I could go from 9.9 CuFt to 6 and still be in the mid 40's. I may have to give this a try. Gene

[GeneT]

You know if I rebuild the cabinets I may just have to update the supporting cast of speakers. Any reccomendations on mid ranges and tweeters that would go with D130F's? Cross over frequencies?
The wife won't mind, women in love are blind .

[clmrt]

075 / 2402's

N2400



http://www.lansingheritage.org/image...1967/chart.jpg

[Zilch]

We'll after reading a post that "D130 wants 4.6 cuft tuned to 44 Hz for "Extended Bass" alignment"

Yeah, well, read the REST of what was discussed over there, and you'll make small mid/high boxes using them with 2435HPL and PT waveguides, with B380 subs under them.

[I have some recommendations for your 123A-3, also.... ]

[GeneT]

Clmrt, thanks for the chart (and tracking me down across forums). I'll have to do some looking about. Gene

[GeneT]

There is a lot of pride of ownership floating about for the 075's. $400 - $500 for a pair.

[clmrt]

2402's aren't as bad.

[Zilch]

2402's aren't as bad.

If you're just talkin' about the money....

[clmrt]

True!

[GeneT]

Here is an Old Thurston Howell The III quote (Jim Bacus) from Gilgians Island "Anyone who says money can't buy happiness, doesn't know where to shop".

Hoenstly though I don't care if I end up with Ring Radiators or Ringless Radiators as long as I sit down at the end of the day turn on the stereo and put a smile on my face.

Zilch I will go back and give the posts relative to Air Suspension a more careful read.

Here's a question on impedence. The D130F's are 4 ohm. When I originally built these my attitude about the extra midrange I put in and the 3 tweeters was, they are crossed over and I don't really care about the impedence (of the mid and high), as long as it's 4 ohms or greater and the sound comes out balanced. I do have a wire wound pot connected to the tweeters for adjustment. My inclination these days, without really knowing the tweeters mentioned would be to put in 2 8 ohm units in parallel, run them at 4 ohms and put the pot in to balance them. I'd be a bit concerned about a single tweeter keeping up.

As far as subs go I'm close to picking up a HSU Research VTF3-MKII. I've read nothing but good things about HSU and for that matter SVS. Cool thing about HSU is that there is an "ask" function on the web and Dr Hsu himself replied back with server possible suggestions based on setup, room size and room configuration. The man must believe in his product to go to the trouble of personalized service. I emailed on a week end and got a reply back during the week end (Dr. Hsu - get a life!). Pretty impressive. Gene